Earthquake News

After Nisqually quake, need to shore up buildings persists

Seattle Times staff reporter


Ten years after the Nisqually earthquake delivered a gut punch to our complacency, we've repaired the damage, built fire stations that won't collapse, made freeway bridges more robust, and strengthened a courthouse and the region's major trauma hospital.

Yet thousands of homes, offices, apartments, shops and hospitals have yet to be bolstered, and for many emergency planners, progress has been agonizingly slow.

There's no mystery about what needs to be done. What's lacking is money, a sense of urgency and a carrot or a stick to motivate private property owners.

Experts point to last week's deadly quake in New Zealand as a reminder of what could happen here.

A quake on the Seattle Fault would bring a similar type of shaking — and quite likely more powerful — along a line that slices through Seattle, Mercer Island and Bellevue, beneath a mix of old and new structures.

"That dated construction is what we're principally worried about," said MRP Engineering President Mark Pierepiekarz, who co-authored a 2005 report on the probable effects of a shallow, magnitude 6.7 quake.

For brick structures that haven't been reinforced since they were built decades ago, damage "can be catastrophic," Pierepiekarz said. But because seismic reinforcement is expensive, most property owners aren't doing it unless they are remodeling a building.

Public agencies also are struggling to pay for improvements. In two of the most noteworthy cases — the need to replace the vulnerable Alaskan Way Viaduct and Highway 520 floating bridge — work is just getting started after years of planning and debate.

The Puget Sound region is better prepared today than it was on Feb. 28, 2001, when an earthquake injured 320 people and caused up to $4 billion damage to buildings, roads and airports.

Because the Nisqually quake occurred deep underground and miles from Seattle, it packed far less of a wallop than two other scenarios that have come before and will come again: a much more powerful "megaquake," where tectonic plates meet, or a shallow quake on the Seattle Fault.

Either kind of event could shake the ground hard enough to demolish unreinforced brick buildings, concrete tilt-up warehouses and office buildings, older multistory concrete structures without adequate steel rebar — and, in the controversial view of one prominent engineer, downtown towers built to current standards.

"Too often in our Pacific Northwest mindset, because we've been through something like the Nisqually earthquake, we think we know what it's like to go through a big earthquake. That's false security," said Seattle Emergency Management Director Barb Graff.

When a 2005 analysis sponsored by the Earthquake Engineering Research Institute and the state Emergency Management Division studied what would happen in a shallow Seattle Fault quake, it projected 1,660 deaths, 24,000 injuries, 9,700 buildings destroyed and $33 billion in property damage.

The Alaskan Way Viaduct would partially or completely collapse, some pre-1941 midrise buildings could collapse, and three-quarters of King County's hospital beds could be knocked out of commission for days or weeks, the experts concluded.

Fortunately, seismic upgrades have been made, along with repairs of Nisqually quake damage, by public and private owners of landmark properties.

The King County Courthouse and Seattle-Tacoma International Airport control tower, for example, were brought up to current standards. The state Capitol, whose sandstone columns shifted perilously in 2001, got a seismic overhaul.

Harborview Medical Center was made quake-resistant through a bond issue approved by voters before Nisqually, while area public schools — which mostly avoided severe damage thanks to voter-approved upgrades — are continuing to make improvements.

Some of the more heavily damaged private properties, including the Compass Center, Cadillac Hotel and Seattle Hebrew Academy, also were repaired and upgraded.

Slow, steady progress

The state Department of Transportation has made slow, steady progress upgrading bridges since the disastrous collapse in 1989 of a double-deck viaduct on the Nimitz Freeway in Oakland, Calif. But even with the 2005 gas tax providing $38 million this biennium, the job won't be done until about 2070.

In the first five years after the quake, the Federal Emergency Management Agency, Small Business Administration and Federal Highway Administration provided $334 million for rebuilding and retrofitting.

Beyond buildings and roads, officials are also working to protect coastal residents from tsunamis. With the help of the state and the University of Washington, counties are developing "vertical evacuation" plans for tsunamis that don't leave enough time for conventional evacuation by vehicles.

Pacific County has developed a plan — with no funding yet — to build 13 berms, five towers and two parking garages where people can ride out a 22-foot-high killer wave. Although there should be 40 minutes warning of a locally triggered tsunami, the plan locates facilities so people could reach them on foot within 15 minutes.

"This is really cutting-edge stuff. This is one of the most exciting projects I've worked with in my entire career," said the state's earthquake program manager, John Schelling.

Engineers know how to strengthen 800 unreinforced brick buildings concentrated largely in Pioneer Square, the Central Area and the University District. Two-thirds of the buildings closed at least temporarily after the 2001 earthquake were brick.

Shaking money loose

Bringing them up to code would cost a lot: $25 to $60 per square foot, according to 2008 city figures. That's more than most property owners are prepared to spend, unless they're doing a larger remodel, Seattle planning officials say.

After the quake, Seattle formed committees to investigate whether owners of brick should be required to bring them up to current seismic standards, as many California cities have done.

The effort stalled.

Tax incentives were considered along with the possible use of police powers.

But committee participant Bob Freitag said, "We didn't have the money to defer taxes and we felt we couldn't put additional burdens on property owners when people can't afford electricity for heat."

Nor has Seattle or the Port of Seattle rebuilt sea walls to prevent parts of the central waterfront and Harbor Island from sliding into the water during a quake.

The city is planning an estimated $300 million replacement of the central waterfront sea wall, with funds potentially coming from the Army Corps of Engineers, King County Flood District and city taxes.

Although the Port seismically strengthened Terminal 91 for cruise ships, it doesn't have a plan to prevent underwater landslides at its container-shipping terminals.

Dakota Chamberlain, director of seaport project management, said he wasn't aware of the 2005 Seattle Fault study that said a slide could put parts of the Port out of business for months.

The same study warned of possible collapses of some pre-1941 buildings of up to 15 stories and eight-to-40-story buildings built between 1941 and 1974. High-rises built after 1975 "should survive," the authors said.

But Peter Yanev, an Orinda, Calif., structural engineer and earthquake consultant, upset many colleagues with an op-ed piece in The New York Times last year arguing that modern skyscrapers in Seattle could suffer severe damage or collapse in a megaquake.

"The buildings in Seattle, no matter what an engineer says, are not designed for a magnitude 9 earthquake, period. If we have an earthquake like Chile, yes, I expect collapses," Yanev said in an interview. Yanev lacks the faith of many of his engineering colleagues in the safety of towers built around a central core and lacking what he considers a sufficient number of walls or other structural "redundancy."

Stacy Bartoletti, president and chief executive officer of Degenkolb Engineers, said he expects to see "significant damage" to some towers, "but we will definitely not see collapse of a major high-rise or all of our high-rises in Seattle. The question in my mind is how many of our high-rises will be unusable after an earthquake and how long will it take to make them usable."

Instead of worrying about downtown towers, say Bartoletti and Pierepiekarz, safety efforts should focus first on a universally recognized danger: older brick and concrete buildings that are subject to life-threatening damage or collapse.

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